U.S. patent application number 12/639289 was filed with the patent office on 2010-06-24 for processing biomass.
This patent application is currently assigned to XYLECO, INC.. Invention is credited to Thomas Craig Masterman, Marshall Medoff.
Application Number | 20100159569 12/639289 |
Document ID | / |
Family ID | 41582003 |
Filed Date | 2010-06-24 |
United States Patent
Application |
20100159569 |
Kind Code |
A1 |
Medoff; Marshall ; et
al. |
June 24, 2010 |
PROCESSING BIOMASS
Abstract
Biomass (e.g., plant biomass, animal biomass, and municipal
waste biomass) is processed to produce useful products, such as
fuels. For example, systems are described that can use feedstock
materials, such as cellulosic and/or lignocellulosic materials
and/or starchy materials, to produce ethanol and/or butanol, e.g.,
by fermentation.
Inventors: |
Medoff; Marshall;
(Brookline, MA) ; Masterman; Thomas Craig;
(Brookline, MA) |
Correspondence
Address: |
Xyleco, Inc.;Celia Leber
2682 N.W. Shields Dr.
Bend
OR
97701
US
|
Assignee: |
XYLECO, INC.
Woburn
MA
|
Family ID: |
41582003 |
Appl. No.: |
12/639289 |
Filed: |
December 16, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61139473 |
Dec 19, 2008 |
|
|
|
Current U.S.
Class: |
435/277 ;
536/56 |
Current CPC
Class: |
C12P 2201/00 20130101;
C12P 7/10 20130101; C08B 15/00 20130101; Y02E 50/30 20130101; C10G
11/02 20130101; C08H 8/00 20130101; Y02E 50/10 20130101; D21C 9/001
20130101; C12P 7/16 20130101; C08L 97/02 20130101; Y02E 50/32
20130101; C12P 19/04 20130101; Y02E 50/16 20130101; C10G 1/00
20130101 |
Class at
Publication: |
435/277 ;
536/56 |
International
Class: |
C08B 15/00 20060101
C08B015/00 |
Claims
1. A method of reducing recalcitrance in cellulosic or
lignocellulosic materials, the method comprising: contacting, in a
mixture, a first cellulosic or lignocellulosic material having a
first level of recalcitrance with one or more compounds comprising
one or more naturally-occurring, non-radioactive group 5, 6, 7, 8,
9, 10 or 11 elements, to produce a second cellulosic or
lignocellulosic material having a second level of recalcitrance
lower than the first level of recalcitrance.
2. The method of claim 1, wherein the one or more elements are in a
1+, 2+, 3+, 4+ or 5+ oxidation state.
3. The method of claim 1, wherein the one or more elements comprise
Mn, Fe, Co, Ni, Cu or Zn.
4. The method of claim 1, wherein the one or more elements comprise
Fe in the 2+, 3+ or 4+ oxidation state.
5. The method of claim 1, wherein the mixture further comprises one
or more oxidants capable of increasing an oxidation state of at
least some of said elements.
6. The method of claim 5 in which the oxidant comprises ozone
and/or hydrogen peroxide.
7. The method of claim 1 further comprising maintaining pH at or
below about 5.5 during contact.
8. The method of claim 5 further comprising dispersing the first
cellulosic or lignocellulosic material in water or an aqueous
medium, and then adding first the one or more compounds and then
the one or more oxidants.
9. The method of claim 5 further comprising dispersing the first
cellulosic or lignocellulosic material in water or an aqueous
medium, and then adding first the one or more oxidants and then the
one or more compounds.
10. The method of claim 1, wherein a total maximum concentration of
the elements in the one or more compounds measured in the
dispersion is from about 10 .mu.M to about 500 mM.
11. The method of claim 5, wherein a total maximum concentration of
the one or more oxidants is from about 100 .mu.M to about 1 M.
12. The method of claim 5 in which the one or more oxidants are
applied to the first cellulosic or lignocellulosic material and the
one or more compounds as a gas, such as by generating ozone in-situ
by irradiating the first cellulosic or lignocellulosic and the one
or more compounds through air with a beam of particles
13. The method of claim 12 wherein the particles are selected from
the group consisting of electrons and protons.
14. The method of claim 1 wherein the mixture includes one or more
compounds and one or more oxidants, and wherein a mole ratio of the
element(s) in the one or more compounds to the one or more oxidants
is from about 1:1000 to about 1:25.
15. The method of claim 1, wherein the mixture further includes one
or more hydroquinones and/or one or more benzoquinones.
16. The method of claim 5, wherein the one or more oxidants are
electrochemically or electromagnetically generated in-situ.
17. A composition comprising 1) a cellulosic or lignocellulosic
material, 2) one or more compounds comprising one or more
naturally-occurring, non-radioactive group 5, 6, 7, 8, 9, 10 or 11
elements, and, optionally, 3) one or more oxidants capable of
increasing an oxidation state of at least some of said
elements.
18. A method of reducing recalcitrance in cellulosic or
lignocellulosic materials, the method comprising: contacting a
first lignocellulosic material having a first level of
recalcitrance with one or more ligninases and/or one or more
biomass-destroying organisms, to produce a second lignocellulosic
material having a second level of recalcitrance lower than the
first level of recalcitrance and contacting the second
lignocellulosic material with an enzyme and/or microorganism.
19. The method of claim 18, wherein the ligninases are selected
from the group consisting of manganese peroxidases, lignin
peroxidases, laccases and mixtures thereof.
20. The method of claim 18, wherein the biomass-destroying
organisms are selected from the group consisting of white rot,
brown rot, soft rot and mixtures thereof.
21. The method of claim 1, wherein the method further comprises
contacting the second cellulosic or lignocellulosic material with
an enzyme and/or microorganism.
22. The method of claim 1, wherein the method further comprises
saccharifying the reduced recalcitrance material and then
fermenting the saccharified material.
Description
RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional
Application Ser. No. 61/139,473 filed Dec. 19, 2008. The complete
disclosure of this provisional application is hereby incorporated
by reference herein.
BACKGROUND
[0002] Various carbohydrates, such as cellulosic and
lignocellulosic materials, e.g., in fibrous form, are produced,
processed, and used in large quantities in a number of
applications. Often such materials are used once, and then
discarded as waste, or are simply considered to be waste materials,
e.g., sewage, bagasse, sawdust, and stover.
[0003] Various cellulosic and lignocellulosic materials, their
uses, and applications have been described, for example, in U.S.
Pat. Nos. 7,307,108, 7,074,918, 6,448,307, 6,258,876, 6,207,729,
5,973,035 and 5,952,105.
SUMMARY
[0004] Generally, this invention relates to carbohydrate-containing
materials (e.g., biomass materials or biomass-derived materials,
such as starchy materials and/or cellulosic or lignocellulosic
materials), methods of making and processing such materials to
change their structure and/or their recalcitrance level, and
products made from the changed materials. For example, many of the
methods described herein can provide cellulosic and/or
lignocellulosic materials that have an oxygen-rich functionality, a
lower molecular weight and/or crystallinity relative to a native
material. Many of the methods, such as Fenton oxidation methods,
provide materials that can be more readily utilized by a variety of
microorganisms (with or without enzymatic hydrolysis) to produce
useful products, such as hydrogen, alcohols (e.g., ethanol or
butanol), organic acids (e.g., acetic acid), hydrocarbons,
co-products (e.g., proteins) or mixtures of any of these. Many of
the products obtained, such as ethanol or n-butanol, can be
utilized as fuel, e.g., as an internal combustion fuel or as a fuel
cell feedstock. In addition, the products described herein can be
utilized for electrical power generation, e.g., in a conventional
steam generating plant or in a fuel cell plant.
[0005] In one aspect, the invention features methods of changing
molecular structures and/or reducing recalcitrance in materials,
such as hydrocarbon-containing materials and/or biomass materials,
e.g., cellulosic or lignocellulosic materials, such as any one or
more unprocessed (e.g., cut grass), semi-processed (e.g.,
comminuted grass) or processed materials (e.g., comminuted and
irradiated grass) described herein.
[0006] The methods can feature oxidative methods of reducing
recalcitrance in cellulosic or lignocellulosic materials that
employ Fenton-type chemistry. Fenton-type chemistry is discussed in
Pestovsky et al., Angew. Chem., Int. Ed. 2005, 44, 6871-6874, the
entire disclosure of which is hereby incorporated by reference
herein. The methods can also feature combinations of Fenton
oxidation and any other pretreatment method described herein in any
order.
[0007] Without wishing to be bound by any particular theory, it is
believed that oxidation increases the number of hydrogen-bonding
groups on the cellulose and/or the lignin, such as hydroxyl groups,
aldehyde groups, ketone groups carboxylic acid groups or anhydride
groups, which can increase its dispersability and/or its
solubility.
[0008] In one aspect, the invention features methods that include
contacting, in a mixture, a first cellulosic or lignocellulosic
material having a first level of recalcitrance with one or more
compounds comprising one or more naturally-occurring,
non-radioactive metallic elements, e.g., non-radioactive group 5,
6, 7, 8, 9, 10 or 11 elements, and, optionally, one or more
oxidants capable of increasing an oxidation state of at least some
of said elements, to produce a second cellulosic or lignocellulosic
material having a second level of recalcitrance lower than the
first level of recalcitrance.
[0009] Other methods include combining a hydrocarbon-containing
material with one or more compounds including one or more
naturally-occurring, non-radioactive metallic elements, e.g.,
non-radioactive group 5, 6, 7, 8, 9, 10 or 11 elements to provide a
mixture in which the one or more compounds contact the
hydrocarbon-containing material; and maintaining the contact for a
period of time and under conditions sufficient to change the
structure of the hydrocarbon-containing material.
[0010] In some embodiments, the method further includes combining
the first cellulosic, lignocellulosic, or hydrocarbon-containing
material with one or more oxidants capable of increasing an
oxidation state of at least some of the elements. In such
instances, the one or more oxidants contact the material with the
one or more compounds in the mixture. In some embodiments, the one
or more oxidants include ozone and/or hydrogen peroxide.
[0011] In some embodiments, the one or more elements are in a 1+,
2+, 3+, 4+ or 5+ oxidation state. In particular instances, the one
or more elements are in a 2+, 3+ or 4+ oxidation state. For
example, iron can be in the form of iron(II), iron(III) or
iron(IV).
[0012] In particular instances, the one or more elements include
Mn, Fe, Co, Ni, Cu or Zn, preferably Fe or Co. For example, the Fe
or Co can be in the form of a sulfate, e.g., iron(II) or iron(III)
sulfate.
[0013] In some embodiments, the one or more oxidants are applied to
the first cellulosic or lignocellulosic material and the one or
more compounds as a gas, such as by generating ozone in-situ by
irradiating the first cellulosic or lignocellulosic material and
the one or more compounds through air with a beam of particles,
such as electrons or protons.
[0014] In some embodiments, the mixture further includes one or
more hydroquinones, such as 2,5-dimethoxyhydroquinone and/or one or
more benzoquinones, such as 2,5-dimethoxy-1,4-benzoquinone. Such
compounds, which have similar molecular entities as lignin, can aid
in electron transfer.
[0015] In some desirable embodiments, the one or more oxidants are
electrochemically or electromagnetically generated in-situ. For
example, hydrogen peroxide and/or ozone can be electrochemically or
electromagnetically produced within a contact or reaction vessel or
outside the vessel and transferred into the vessel.
[0016] The methods may further include contacting the second
cellulosic or lignocellulosic material with an enzyme and/or
microorganism. Products produced by such contact can include any of
those products described herein, such as food or fuel, e.g.,
ethanol, or any other products described in U.S. Provisional
Application Ser. No. 61/139,453, which is hereby incorporated by
reference herein in its entirety.
[0017] In another aspect, the invention features systems that
include a structure or carrier, e.g., a reaction vessel, containing
a mixture including 1) any material described herein, such as a
cellulosic or lignocellulosic material and 2) one or more compounds
comprising one or more naturally-occurring, non-radioactive
metallic elements, e.g., non-radioactive group 5, 6, 7, 8, 9, 10 or
11 elements. Optionally, the mixture can include 3) one or more
oxidants capable of increasing an oxidation state of at least some
of the elements.
[0018] In another aspect, the invention features compositions that
include 1) any material described herein, such as a cellulosic or
lignocellulosic material and 2) one or more compounds comprising
one or more naturally-occurring, non-radioactive group 5, 6, 7, 8,
9, 10 or 11 elements. Optionally, the composition can include one
or more oxidants capable of increasing an oxidation state of at
least some of the elements.
[0019] In another aspect, the invention features methods of
changing molecular structures and/or reducing recalcitrance in
biomass materials, such as cellulosic or lignocellulosic materials.
The methods include combining a first lignocellulosic material
having a first level of recalcitrance with one or more ligninases
and/or one or more biomass-destroying, e.g., lignin-destroying
organisms, in a manner that the one or more ligninases and/or
organisms contact the first cellulosic or lignocellulosic material;
and maintaining the contact for a period of time and under
conditions sufficient to produce a second lignocellulosic material
having a second level of recalcitrance lower than the first level
of recalcitrance. The method can further include contacting the
second cellulosic or lignocellulosic material with an enzyme and/or
microorganism, e.g., to make any product described herein, e.g.,
food or fuel, e.g., ethanol or butanol (e.g., n-butanol) or any
product described in U.S. Provisional Application Ser. No.
61/139,453.
[0020] The ligninase can be, e.g., one or more of manganese
peroxidase, lignin peroxidase or laccases.
[0021] The biomass-destroying organism can be, e.g., one or more of
white rot, brown rot or soft rot. For example, the
biomass-destroying organism can be a Basidiomycetes fungus. In
particular embodiments, the biomass-destroying organism is
Phanerochaete chrysoporium or Gleophyllum trabeum.
[0022] In certain embodiments, the first material is in the form of
a fibrous material that includes fibers provided by shearing a
fiber source. Shearing alone can reduce the crystallinity of a
fibrous material and can work synergistically with any process
technique that also reduces crystallinity and/or molecular weight.
For example, the shearing can be performed with a rotary knife
cutter. In some embodiments, the fibrous material has an average
length-to-diameter ratio of greater than 5/1.
[0023] The first and/or second material can have, e.g., a BET
surface area of greater than 0.25 m.sup.2/g and/or a porosity of
greater than about 25 percent.
[0024] To further aid in the reduction of the molecular weight of
the cellulose, an enzyme, e.g., a cellulolytic enzyme, or a
chemical, e.g., sodium hypochlorite, an acid, a base or a swelling
agent, can be utilized with any method described herein.
[0025] When a microorganism is utilized, it can be a natural
microorganism or an engineered microorganism. For example, the
microorganism can be a bacterium, e.g., a cellulolytic bacterium, a
fungus, e.g., a yeast, an enzyme, a plant or a protist, e.g., an
algae, a protozoa or a fungus-like protist, e.g., a slime mold.
When the organisms are compatible, mixtures may be utilized.
Generally, various microorganisms can produce a number of useful
products, such as a fuel, by operating on, e.g., fermenting the
materials. For example, alcohols, organic acids, hydrocarbons,
hydrogen, proteins or mixtures of any of these materials can be
produced by fermentation or other processes.
[0026] Examples of products that may be produced include mono- and
polyfunctional C1-C6 alkyl alcohols, mono- and poly-functional
carboxylic acids, C1-C6 hydrocarbons, and combinations thereof.
Specific examples of suitable alcohols include methanol, ethanol,
propanol, isopropanol, butanol, ethylene glycol, propylene glycol,
1,4-butane diol, glycerin, and combinations thereof. Specific
example of suitable carboxylic acids include formic acid, acetic
acid, propionic acid, butyric acid, valeric acid, caproic acid,
palmitic acid, stearic acid, oxalic acid, malonic acid, succinic
acid, glutaric acid, oleic acid, linoleic acid, glycolic acid,
lactic acid, .gamma.-hydroxybutyric acid, and combinations thereof.
Examples of suitable hydrocarbons include methane, ethane, propane,
pentane, n-hexane, and combinations thereof. Many of these products
may be used as fuels.
[0027] The term "fibrous material," as used herein, is a material
that includes numerous loose, discrete and separable fibers. For
example, a fibrous material can be prepared from a bleached Kraft
paper fiber source by shearing, e.g., with a rotary knife
cutter.
[0028] The term "screen," as used herein, means a member capable of
sieving material according to size. Examples of screens include a
perforated plate, cylinder or the like, or a wire mesh or cloth
fabric.
[0029] The term "pyrolysis," as used herein, means to break bonds
in a material by the application of heat energy. Pyrolysis can
occur while the subject material is under vacuum, or immersed in a
gaseous material, such as an oxidizing gas, e.g., air or oxygen, or
a reducing gas, such as hydrogen.
[0030] Oxygen content is measured by elemental analysis by
pyrolyzing a sample in a furnace operating at 1300.degree. C. or
above.
[0031] Examples of biomass feedstock include paper, paper products,
paper waste, wood, wood wastes and residues, particle board,
sawdust, agricultural waste and crop residues, sewage, silage,
grasses, rice hulls, bagasse, cotton, jute, hemp, flax, bamboo,
sisal, abaca, straw, corn cobs, corn stover, switchgrass, alfalfa,
hay, rice hulls, coconut hair, cotton, synthetic celluloses,
seaweed, algae, municipal waste, or mixtures of these. The biomass
can be or can include a natural or a synthetic material.
[0032] The terms "plant biomass" and "lignocellulosic biomass"
refer to virtually any plant-derived organic matter (woody or
non-woody).
[0033] For the purposes of this disclosure, carbohydrates are
materials that are composed entirely of one or more saccharide
units or that include one or more saccharide units. Carbohydrates
can be polymeric (e.g., equal to or greater than 10-mer, 100-mer,
1,000-mer, 10,000-mer, or 100,000-mer), oligomeric (e.g., equal to
or greater than a 4-mer, 5-mer, 6-mer, 7-mer, 8-mer, 9-mer or
10-mer), trimeric, dimeric, or monomeric. When the carbohydrates
are formed of more than a single repeat unit, each repeat unit can
be the same or different. Examples of polymeric carbohydrates
include cellulose, xylan, pectin, and starch, while cellobiose and
lactose are examples of dimeric carbohydrates. Examples of
monomeric carbohydrates include glucose and xylose. Carbohydrates
can be part of a supramolecular structure, e.g., covalently bonded
into the structure. Examples of such materials include
lignocellulosic materials, such as that found in wood.
[0034] A starchy material is one that is or includes significant
amounts of starch or a starch derivative, such as greater than
about 5 percent by weight starch or starch derivative. For purposes
of this disclosure, a starch is a material that is or includes an
amylose, an amylopectin, or a physical and/or chemical mixture
thereof, e.g., a 20:80 or 30:70 percent by weight mixture of
amylose to amylopectin. For example, rice, corn, and mixtures
thereof are starchy materials. Starch derivatives include, e.g.,
maltodextrin, acid-modified starch, base-modified starch, bleached
starch, oxidized starch, acetylated starch, acetylated and oxidized
starch, phosphate-modified starch, genetically-modified starch and
starch that is resistant to digestion.
[0035] Swelling agents as used herein are materials that cause a
discernable swelling, e.g., a 2.5 percent increase in volume over
an unswollen state of cellulosic and/or lignocellulosic materials,
when applied to such materials as a solution, e.g., a water
solution. Examples include alkaline substances, such as sodium
hydroxide, potassium hydroxide, lithium hydroxide and ammonium
hydroxides, acidifying agents, such as mineral acids (e.g.,
sulfuric acid, hydrochloric acid and phosphoric acid), salts, such
as zinc chloride, calcium carbonate, sodium carbonate,
benzyltrimethylammonium sulfate, and basic organic amines, such as
ethylene diamine.
[0036] A "sheared material," as used herein, is a material that
includes discrete fibers in which at least about 50% of the
discrete fibers, have a length/diameter (L/D) ratio of at least
about 5, and that has an uncompressed bulk density of less than
about 0.6 g/cm.sup.3. A sheared material is thus different from a
material that has been cut, chopped or ground.
[0037] Changing a molecular structure of a biomass feedstock, as
used herein, means to change the chemical bonding arrangement or
conformation of the structure. For example, the change in the
molecular structure can include changing the supramolecular
structure of the material, oxidation of the material, changing an
average molecular weight, changing an average crystallinity,
changing a surface area, changing a degree of polymerization,
changing a porosity, changing a degree of branching, grafting on
other materials, changing a crystalline domain size, or an changing
an overall domain size.
[0038] Unless otherwise defined, all technical and scientific terms
used herein have the same meaning as commonly understood by one of
ordinary skill in the art to which this invention belongs. All
publications, patent applications, patents, and other references
mentioned herein or attached hereto are incorporated by reference
in their entirety for all that they contain.
[0039] Any biomass material, e.g., carbohydrate-containing
material, e.g., cellulosic and/or lignocellulosic material
described herein can be utilized in any application or process
described in any patent or patent application incorporated by
reference herein.
[0040] Other features and advantages of the invention will be
apparent from the following detailed description, and from the
claims.
DESCRIPTION OF DRAWINGS
[0041] FIG. 1 is block diagram illustrating conversion of a fiber
source into a first and second fibrous material.
[0042] FIG. 2 is a cross-sectional view of a rotary knife
cutter.
[0043] FIG. 3 is block diagram illustrating conversion of a fiber
source into a first, second and third fibrous material.
[0044] FIG. 4 is a schematic cross-sectional side view of a
reactor.
[0045] FIG. 5 shows a sequence of chemical reactions illustrating
Fenton chemistry.
[0046] FIG. 6 shows a sequence of Fenton reactions illustrating
conversion of benzene to phenol and toluene to benzaldehyde and
benzyl alcohol.
[0047] FIG. 7 shows a reaction scheme for the preparation of a
reactive iron (IV) compound from an iron (II) compound.
[0048] FIG. 8 shows a proposed pathway for reduction of Fe (III)
and production of hydrogen peroxide in the presence of
2,5-dimethoxyhydroquinone.
[0049] FIG. 9 is a scanning electron micrograph of a fibrous
material produced from polycoated paper at 25.times. magnification.
The fibrous material was produced on a rotary knife cutter
utilizing a screen with 1/8 inch openings.
[0050] FIG. 10 is a scanning electron micrograph of a fibrous
material produced from bleached Kraft board paper at 25.times.
magnification. The fibrous material was produced on a rotary knife
cutter utilizing a screen with 1/8 inch openings.
[0051] FIG. 11 is a scanning electron micrograph of a fibrous
material produced from bleached Kraft board paper at 25.times.
magnification. The fibrous material was twice sheared on a rotary
knife cutter utilizing a screen with 1/16 inch openings during each
shearing.
[0052] FIG. 12 is a scanning electron micrograph of a fibrous
material produced from bleached Kraft board paper at 25.times.
magnification. The fibrous material was thrice sheared on a rotary
knife cutter. During the first shearing, a 1/8 inch screen was
used; during the second shearing, a 1/16 inch screen was used, and
during the third shearing a 1/32 inch screen was used.
DETAILED DESCRIPTION
[0053] Using the methods described herein, biomass can be processed
to a lower level of recalcitrance and converted into useful
products such as fuels. Systems and processes are described below
that can use as feedstocks materials such as cellulosic and/or
lignocellulosic materials that are readily available, but can be
difficult to process, for example, by saccharification and/or by
fermentation. In some implementations the feedstock materials are
first physically prepared for processing, for example by size
reduction. The physically prepared feedstock is then pretreated
using oxidation (e.g., using Fenton-type chemistry), and may in
some cases be further treated with one or more of radiation,
sonication, pyrolysis, and steam explosion. Alternatively, in some
cases, the feedstock is first treated with one or more of
radiation, sonication, pyrolysis, and steam explosion, and then
treated using oxidation, e.g., Fenton-type chemistry.
[0054] Preferred oxidative methods for reducing recalcitrance in
cellulosic or lignocellulosic materials include Fenton-type
chemistry, discussed above, in which one or more group 5, 6, 7, 8,
9, 10 or 11 elements, optionally along with one or more oxidants
capable of increasing an oxidation state of at least some of the
elements are utilized.
[0055] After pretreatment, the pretreated material can be further
processed, e.g., using primary processes such as saccharification
and/or fermentation, to produce a product.
Types of Biomass
[0056] Generally, any biomass material that is or includes
carbohydrates composed entirely of one or more saccharide units or
that include one or more saccharide units can be processed by any
of the methods described herein. For example, the biomass material
can be cellulosic or lignocellulosic materials, or starchy
materials, such as kernels of corn, grains of rice or other
foods.
[0057] Fiber sources include cellulosic fiber sources, including
paper and paper products (e.g., polycoated paper and Kraft paper),
and lignocellulosic fiber sources, including wood, and wood-related
materials, e.g., particle board. Other suitable fiber sources
include natural fiber sources, e.g., grasses, rice hulls, bagasse,
cotton, jute, hemp, flax, bamboo, sisal, abaca, straw, corn cobs,
rice hulls, coconut hair; fiber sources high in .alpha.-cellulose
content, e.g., cotton; and synthetic fiber sources, e.g., extruded
yarn (oriented yarn or un-oriented yarn). Natural or synthetic
fiber sources can be obtained from virgin scrap textile materials,
e.g., remnants or they can be post consumer waste, e.g., rags. When
paper products are used as fiber sources, they can be virgin
materials, e.g., scrap virgin materials, or they can be
post-consumer waste. Aside from virgin raw materials,
post-consumer, industrial (e.g., offal), and processing waste
(e.g., effluent from paper processing) can also be used as fiber
sources. Also, the fiber source can be obtained or derived from
human (e.g., sewage), animal or plant wastes. Additional fiber
sources have been described in U.S. Pat. Nos. 6,448,307, 6,258,876,
6,207,729, 5,973,035 and 5,952,105, the full disclosures of which
are incorporated by reference herein.
[0058] Starchy materials include starch itself, e.g., corn starch,
wheat starch, potato starch or rice starch, a derivative of starch,
or a material that includes starch, such as an edible food product
or a crop. For example, the starchy material can be arracacha,
buckwheat, banana, barley, cassava, kudzu, oca, sago, sorghum,
regular household potatoes, sweet potato, taro, yams, or one or
more beans, such as favas, lentils or peas. Blends of any one or
more starchy material is also a starchy material. In particular
embodiments, the starchy material is derived from corn. Various
corn starches and derivatives are described in "Corn Starch," Corn
Refiners Association (11.sup.th Edition, 2006), which is hereby
incorporated by reference herein.
[0059] Blends of any biomass materials described herein can be
utilized for making any of the products described herein, such as
ethanol. For example, blends of cellulosic materials and starchy
materials can be utilized for making any product described
herein.
Feed Preparation
[0060] In some cases, methods of processing begin with a physical
preparation of the feedstock, e.g., size reduction of raw feedstock
materials, such as by cutting, grinding, shearing or chopping. In
some cases, loose feedstock (e.g., recycled paper, starchy
materials, or switchgrass) is prepared by shearing or shredding.
Screens and/or magnets can be used to remove oversized or
undesirable objects such as, for example, rocks or nails from the
feed stream.
[0061] Feed preparation systems can be configured to produce feed
streams with specific characteristics such as, for example,
specific maximum sizes, specific length-to-width, or specific
surface areas ratios. As a part of feed preparation, the bulk
density of feedstocks can be controlled (e.g., increased). If
desired, lignin can be removed from any feedstock that includes
lignin.
Size Reduction
[0062] In some embodiments, the material to be processed is in the
form of a fibrous material that includes fibers provided by
shearing a fiber source. For example, the shearing can be performed
with a rotary knife cutter.
[0063] For example, and by reference to FIG. 1, a fiber source 210
is sheared, e.g., in a rotary knife cutter, to provide a first
fibrous material 212. The first fibrous material 212 is passed
through a first screen 214 having an average opening size of 1.59
mm or less ( 1/16 inch, 0.0625 inch) to provide a second fibrous
material 216. If desired, fiber source can be cut prior to the
shearing, e.g., with a shredder.
[0064] In some embodiments, the shearing of fiber source and the
passing of the resulting first fibrous material through first
screen are performed concurrently. The shearing and the passing can
also be performed in a batch-type process.
[0065] For example, a rotary knife cutter can be used to
concurrently shear the fiber source and screen the first fibrous
material. Other methods of making the fibrous materials include,
e.g., stone grinding, mechanical ripping or tearing, pin grinding
or air attrition milling. Referring to FIG. 2, a rotary knife
cutter 220 includes a hopper 222 that can be loaded with a shredded
fiber source 224. The shredded fiber source is sheared between
stationary blades 230 and rotating blades 232 to provide a first
fibrous material 240. First fibrous material 240 passes through
screen 242, and the resulting second fibrous material 244 is
captured in bin 250. To aid in the collection of the second fibrous
material, a vacuum source 252 can be utilized to maintain the bin
at a pressure below nominal atmospheric pressure, e.g., at least
10, 25, 50 or 75 percent below nominal atmospheric pressure.
[0066] Shearing can be advantageous for "opening up" and
"stressing" the fibrous materials, making the cellulose of the
materials more susceptible to chain scission and/or reduction of
crystallinity. The open materials can also be more susceptible to
oxidation.
[0067] The fiber source can be sheared in a dry state, a hydrated
state (e.g., having up to ten percent by weight absorbed water), or
in a wet state, e.g., having between about 10 percent and about 75
percent by weight water. The fiber source can even be sheared while
partially or fully submerged under a liquid, such as water,
ethanol, isopropanol. The fiber source can also be sheared under a
gas (such as a stream or atmosphere of gas other than air), e.g.,
oxygen or nitrogen, or steam.
[0068] In some embodiments, the average opening size of the first
screen 214 is less than 0.79 mm (0.031 inch), e.g., less than 0.51
mm (0.020 inch), 0.40 mm (0.015 inch), 0.23 mm (0.009 inch), 0.20
mm (0.008 inch), 0.18 mm (0.007 inch), 0.13 mm (0.005 inch), or
even less than less than 0.10 mm (0.004 inch). The characteristics
of suitable screens are described, for example, in US 2008-0206541.
In some embodiments, the open area of the mesh is less than 52%,
e.g., less than 41%, less than 36%, less than 31%, or less than
30%.
[0069] In some embodiments, the second fibrous is sheared and
passed through the first screen, or a different sized screen. In
some embodiments, the second fibrous material is passed through a
second screen having an average opening size equal to or less than
that of first screen. Referring to FIG. 3, a third fibrous material
220 can be prepared from the second fibrous material 216 by
shearing the second fibrous material 216 and passing the resulting
material through a second screen 222 having an average opening size
less than the first screen 214. In such instances, a ratio of the
average length-to-diameter ratio of the second fibrous material to
the average length-to-diameter ratio of the third fibrous material
can be, e.g., less than 1.5, e.g., less than 1.4, less than 1.25,
or even less than 1.1.
[0070] Generally, the fibers of the fibrous materials can have a
relatively large average length-to-diameter ratio (e.g., greater
than 20-to-1), even if they have been sheared more than once. In
addition, the fibers of the fibrous materials described herein may
have a relatively narrow length and/or length-to-diameter ratio
distribution.
[0071] As used herein, average fiber widths (i.e., diameters) are
those determined optically by randomly selecting approximately
5,000 fibers. Average fiber lengths are corrected length-weighted
lengths. BET (Brunauer, Emmet and Teller) surface areas are
multi-point surface areas, and porosities are those determined by
mercury porosimetry.
[0072] The average length-to-diameter ratio of the second fibrous
material 14 can be, e.g. greater than 8/1, e.g., greater than 10/1,
greater than 15/1, greater than 20/1, greater than 25/1, or greater
than 50/1. An average length of the second fibrous material 14 can
be, e.g., between about 0.5 mm and 2.5 mm, e.g., between about 0.75
mm and 1.0 mm, and an average width (i.e., diameter) of the second
fibrous material 14 can be, e.g., between about 5 .mu.m and 50
.mu.m, e.g., between about 10 .mu.m and 30 .mu.m.
[0073] In some embodiments, a standard deviation of the length of
the second fibrous material 14 is less than 60 percent of an
average length of the second fibrous material 14, e.g., less than
50 percent of the average length, less than 40 percent of the
average length, less than 25 percent of the average length, less
than 10 percent of the average length, less than 5 percent of the
average length, or even less than 1 percent of the average
length.
[0074] In some embodiments, a BET surface area of the second
fibrous material is greater than 0.1 m.sup.2/g, e.g., greater than
0.25 m.sup.2/g, greater than 0.5 m.sup.2/g, greater than 1.0
m.sup.2/g, greater than 1.5 m.sup.2/g, greater than 1.75 m.sup.2/g,
greater than 5.0 m.sup.2/g, greater than 10 m.sup.2/g, greater than
25 m.sup.2/g, greater than 35 m.sup.2/g, greater than 50 m.sup.2/g,
greater than 60 m.sup.2/g, greater than 75 m.sup.2/g, greater than
100 m.sup.2/g, greater than 150 m.sup.2/g, greater than 200
m.sup.2/g, or even greater than 250 m.sup.2/g.
[0075] A porosity of the second fibrous material 14 can be, e.g.,
greater than 20, 25, 35, 50, 60, 70, 80, 85, 90, 92, 94, 95, 97.5
or 99 percent, or even greater than 99.5 percent.
[0076] In some embodiments, a ratio of the average
length-to-diameter ratio of the first fibrous material to the
average length-to-diameter ratio of the second fibrous material is,
e.g., less than 1.5, e.g., less than 1.4, less than 1.25, less than
1.1, less than 1.075, less than 1.05, less than 1.025, or even
substantially equal to 1.
[0077] In some embodiments, the third fibrous material is passed
through a third screen to produce a fourth fibrous material. The
fourth fibrous material can be, e.g., passed through a fourth
screen to produce a fifth material. Similar screening processes can
be repeated as many times as desired to produce the desired fibrous
material having the desired properties.
[0078] In some implementations, the size reduction equipment may be
portable, e.g., in the manner of the mobile processing equipment
described in U.S. Provisional Patent Application Ser. 60/832,735,
now Published International Application No. WO 2008/011598.
Pretreatment
[0079] Physically prepared feedstock can be pretreated for use in
primary production processes such as saccharification and
fermentation by, for example, reducing the average molecular weight
and crystallinity of the feedstock and/or increasing the surface
area and/or porosity of the feedstock. Pretreatment processes
include utilizing Fenton-type chemistry, discussed above, and can
further include one or more of irradiation, sonication, oxidation,
pyrolysis, and steam explosion.
Fenton Chemistry
[0080] In some embodiments, the one or more elements used in the
Fenton reaction are in a 1+, 2+, 3+, 4+ or 5+ oxidation state. In
particular instances, the one or more elements include Mn, Fe, Co,
Ni, Cu or Zn, preferably Fe or Co. For example, the Fe or Co can be
in the form of a sulfate, e.g., iron(II) or iron(III) sulfate. In
particular instances, the one or more elements are in a 2+, 3+ or
4+ oxidation state. For example, iron can be in the form of
iron(II), iron(III) or iron(IV).
[0081] Exemplary iron (II) compounds include ferrous sulfate
heptahydrate, iron(II) acetylacetonate, (+)-iron(II) L-ascorbate,
iron(II) bromide, iron(II) chloride, iron(II) chloride hydrate,
iron(II) chloride tetrahydrate, iron(II) ethylenediammonium sulfate
tetrahydrate, iron(II) fluoride, iron(II) gluconate hydrate,
iron(II) D-gluconate dehydrate, iron(II) iodide, iron(II) lactate
hydrate, iron(II) molybdate, iron(II) oxalate dehydrate, iron(II)
oxide, iron(II,III) oxide, iron(II) perchlorate hydrate, iron(II)
phthalocyanine, iron(II) phthalocyanine bis(pyridine) complex,
iron(II) sulfate heptahydrate, iron(II) sulfate hydrate, iron(II)
sulfide, iron(II) tetrafluoroborate hexahydrate, iron(II) titanate,
ammonium iron(II) sulfate hexahydrate, ammonium iron(II) sulfate,
cyclopentadienyl iron(II) dicarbonyl dimer,
ethylenediaminetetraacetic acid hydrate iron(III) sodium salt and
ferric citrate.
[0082] Exemplary iron (III) compounds include iron(III)
acetylacetonate, iron(III) bromide, iron(III) chloride, iron(III)
chloride hexahydrate, iron(III) chloride solution, iron(III)
chloride on silica gel, iron(III) citrate, tribasic monohydrate,
iron(III) ferrocyanide, iron(III) fluoride, iron(III) fluoride
trihydrate, iron(III) nitrate nonahydrate, iron(III) nitrate on
silica gel, iron(III) oxalate hexahydrate, iron(III) oxide,
iron(III) perchlorate hydrate, iron(III) phosphate, iron(III)
phosphate dehydrate, iron(III) phosphate hydrate, iron(III)
phosphate tetrahydrate, iron(III) phthalocyanine chloride,
iron(III) phthalocyanine-4,4',4'', 4'''-tetrasulfonic acid,
compound with oxygen hydrate monosodium salt, iron(III)
pyrophosphate, iron(III) sulfate hydrate, iron(III)
p-toluenesulfonate hexahydrate, iron(III)
tris(2,2,6,6-tetramethyl-3,5-heptanedionate) and ammonium iron(III)
citrate.
[0083] Exemplary cobalt (II) compounds include cobalt(II) acetate,
cobalt(II) acetate tetrahydrate, cobalt(II) acetylacetonate
hydrate, cobalt(II) benzoylacetonate, cobalt(II) bromide,
cobalt(II) bromide hydrate and cobalt(II) carbonate hydrate.
[0084] Exemplary cobalt (III) compounds include cobalt(III)
acetylacetonate, cobalt(III) fluoride, cobalt(III) oxide,
cobalt(III) sepulchrate trichloride, hexamine cobalt(III) chloride,
bis(cyclopentadienyl)cobalt(III) hexafluorophosphate and
bis(ethylcyclopentadienyl)cobalt(III) hexafluorophosphate.
[0085] Exemplary oxidants include peroxides, such as hydrogen
peroxide and benzoyl peroxide, persulfates, such as ammonium
persulfate, activated forms of oxygen, such as ozone,
permanganates, such as potassium permanganate, perchlorates, such
as sodium perchlorate, and hypochlorites, such as sodium
hypochlorite (household bleach).
[0086] Generally, Fenton oxidation occurs in an oxidizing
environment. For example, the oxidation can be effected or aided by
pyrolysis in an oxidizing environment, such as in air or argon
enriched in air. To aid in the oxidation, various chemical agents,
such as oxidants, acids or bases can be added to the material prior
to or during oxidation. For example, a peroxide (e.g., benzoyl
peroxide) can be added prior to oxidation.
[0087] In some cases, pH is maintained at or below about 5.5 during
contact, such as between 1 and 5, between 2 and 5, between 2.5 and
5 or between about 3 and 5. The contact period may be, for example,
between 2 and 12 hours, e.g., between 4 and 10 hours or between 5
and 8 hours. In some instances, the reaction conditions are
controlled so that the temperature does not exceed 300.degree. C.,
e.g., the temperature remains less than 250, 200, 150, 100 or even
less than 50.degree. C. In some cases, the temperature remains
substantially ambient, e.g., at or about 20-25.degree. C.
[0088] Referring to FIG. 4, reactive mixtures 2108 within a vessel
2110 can be prepared using various approaches. For example, in
instances in which the mixture includes one or more compounds and
one or more oxidants, the first cellulosic or lignocellulosic
material can be first dispersed in water or an aqueous medium, and
then the one or more compounds can be added, followed by addition
of the one or more oxidants. Alternatively, the one or more
oxidants can added, followed by the one or more compounds, or the
one or more oxidants and the one or more compounds can be
concurrently added separately to the dispersion (e.g., each added
independently through a separate addition device 2120, 2122 to the
dispersion).
[0089] In some embodiments, a total maximum concentration of the
elements in the one or more compounds measured in the dispersion is
from about 10 .mu.M to about 500 mM, e.g., between about 25 .mu.M
and about 250 mM or between about 100 .mu.M and about 100 mM,
and/or a total maximum concentration of the one or more oxidants is
from about 100 .mu.M to about 1 M, e.g., between about 250 .mu.M
and about 500 mM, or between about 500 .mu.m and 250 mM. In some
embodiments, the mole ratio of the elements in the one or more
compounds to the one or more oxidants is from about 1:1000 to about
1:25, such as from about 1:500 to about 1:25 or from about 1:100 to
about 1:25.
[0090] In some cases, the one or more oxidants are applied to the
first cellulosic or lignocellulosic material and the one or more
compounds as a gas, such as by generating ozone in-situ by
irradiating the first cellulosic or lignocellulosic and the one or
more compounds through air with a beam of particles, such as
electrons or protons.
[0091] In other cases, the first cellulosic or lignocellulosic
material is first dispersed in water or an aqueous medium that
includes the one or more compounds dispersed and/or dissolved
therein, and then water is removed after a soak time (e.g., loose
and free water is removed by filtration), and then the one or more
oxidants are applied to the combination as a gas, such as by
generating ozone in-situ by irradiating the first cellulosic or
lignocellulosic and the one or more compounds through air with a
beam of particles, such as electrons (e.g., each being accelerated
by a potential difference of between 3 MeV and 10 MeV).
[0092] Referring now to FIG. 5, in some particular embodiments, an
iron (II) compound is utilized for the Fenton-type chemistry, such
as iron (II) sulfate, and hydrogen peroxide is utilized as the
oxidant. FIG. 5 illustrates that in such a system, hydrogen
peroxide oxidizes the iron (II) to generate iron (III), hydroxyl
radicals and hydroxide ions (equation 1). The hydroxyl radicals can
then react with the first cellulosic or lignocellulosic material,
thereby oxidizing it to the second cellulosic or lignocellulosic
material. The iron (III) thus produced can be reduced back to iron
(II) by the action of hydrogen peroxide and hydroperoxyl radicals
(equations 2 and 3). Equation 4 illustrates that it is also
possible for an organic radical (R) to reduce iron (III) back to
iron (II).
[0093] FIG. 6 illustrates that iron (II) sulfate and hydrogen
peroxide in aqueous solutions and at pH below about 6 can oxidize
aromatic rings to give phenols, aldehydes and alcohols. When
applied to cellulosic or lignocellulosic material, these
Fenton-type reactions can help enhance the solubility of the
lignocellulosic material by functionalization of the lignin and/or
cellulose or hemicellulose, and by reduction in molecular weight of
the lignocellulosic material. The net effect of the Fenton-type
reactions on the lignocellulosic material can be a change in
molecular structure and/or a reduction in its recalcitrance.
[0094] FIG. 7 shows that hydrated iron (II) compounds, such as
hydrated iron (II) sulfate, can react with ozone in aqueous
solutions to generate extremely reactive hydrated iron (IV)
compounds that can react with and oxidize cellulosic and
lignocellulosic materials.
[0095] In some desirable embodiments, the mixture further includes
one or more hydroquinones, such as 2,5-dimethoxyhydroquinone (DMHQ)
and/or one or more benzoquinones, such as
2,5-dimethoxy-1,4-benzoquinone (DMBQ), which can aid in electron
transfer reactions. FIG. 8 illustrates how iron (III) can be
reduced by DMHQ to give iron (II) and DMHQ semi-quinone radical.
Addition of oxygen to the semi-quinone then gives
alpha-hydroxyperoxyl radical that eliminates HOO. to give DMBQ.
Finally, HOO. oxidizes iron (II) or dismutates to generate hydrogen
peroxide.
[0096] In some desirable embodiments, the one or more oxidants are
electrochemically or electromagnetically generated in-situ. For
example, hydrogen peroxide and/or ozone can be electrochemically or
electromagnetically produced within a contact or reaction
vessel.
[0097] In some implementations, the Fenton reaction vessel may be
portable, e.g., in the manner of the mobile processing equipment
described in U.S. Provisional Patent Application Ser. 60/832,735,
now Published International Application No. WO 2008/011598.
Radiation Treatment
[0098] Before, during or after the Fenton oxidation discussed
above, one or more irradiation processing sequences can be used to
pretreat the feedstock. Irradiation can reduce the molecular weight
and/or crystallinity of feedstock. In some embodiments, energy
deposited in a material that releases an electron from its atomic
orbital is used to irradiate the materials. The radiation may be
provided by 1) heavy charged particles, such as alpha particles or
protons, 2) electrons, produced, for example, in beta decay or
electron beam accelerators, or 3) electromagnetic radiation, for
example, gamma rays, x rays, or ultraviolet rays. In one approach,
radiation produced by radioactive substances can be used to
irradiate the feedstock. In some embodiments, any combination in
any order or concurrently of (1) through (3) may be utilized. In
another approach, electromagnetic radiation (e.g., produced using
electron beam emitters) can be used to irradiate the feedstock. The
doses applied depend on the desired effect and the particular
feedstock. For example, high doses of radiation can break chemical
bonds within feedstock components and low doses of radiation can
increase chemical bonding (e.g., cross-linking) within feedstock
components. In some instances when chain scission is desirable
and/or polymer chain functionalization is desirable, particles
heavier than electrons, such as protons, helium nuclei, argon ions,
silicon ions, neon ions carbon ions, phosphorus ions, oxygen ions
or nitrogen ions can be utilized. When ring-opening chain scission
is desired, positively charged particles can be utilized for their
Lewis acid properties for enhanced ring-opening chain scission. For
example, when maximum oxidation is desired, oxygen ions can be
utilized, and when maximum nitration is desired, nitrogen ions can
be utilized.
Doses
[0099] In some embodiments, the irradiating (with any radiation
source or a combination of sources) is performed until the material
receives a dose of at least 0.25 Mrad, e.g., at least 1.0 Mrad, 2.5
Mrad, 5.0 Mrad, 10.0 Mrad, 25 Mrad, 50 Mrad, or even at least 100
Mrad. In some embodiments, the irradiating is performed until the
material receives a dose of between 1.0 Mrad and 6.0 Mrad, e.g.,
between 1.5 Mrad and 4.0 Mrad.
[0100] In some embodiments, the irradiating is performed at a dose
rate of between 5.0 and 1500.0 kilorads/hour, e.g., between 10.0
and 750.0 kilorads/hour or between 50.0 and 350.0
kilorads/hours.
[0101] In some embodiments, two or more radiation sources are used,
such as two or more ionizing radiations. For example, samples can
be treated, in any order, with a beam of electrons, followed by
gamma radiation and UV light having wavelengths from about 100 nm
to about 280 nm.
[0102] In some embodiments, relatively low doses of radiation can
crosslink, graft, or otherwise increase the molecular weight of a
carbohydrate-containing material, such as a cellulosic or
lignocellulosic material (e.g., cellulose). For example, a fibrous
material that includes a first cellulosic and/or lignocellulosic
material having a first molecular weight can be irradiated in such
a manner as to provide a second cellulosic and/or lignocellulosic
material having a second molecular weight higher than the first
molecular weight. For example, if gamma radiation is utilized as
the radiation source, a dose of from about 1 Mrad to about 10 Mrad,
about 1 Mrad to about 75 Mrad, or about 1 Mrad to about 100 Mrad
can be applied. In some implementations, from about 1.5 Mrad to
about 7.5 Mrad or from about 2.0 Mrad to about 5.0 Mrad, can be
applied.
Sonication, Pyrolysis, Oxidation, and Steam Explosion
[0103] One or more sonication, pyrolysis, oxidative processing,
and/or steam explosion can be used to further pretreat the
feedstock. Such processing can reduce the molecular weight and/or
crystallinity of feedstock and biomass, e.g., one or more
carbohydrate sources, such as cellulosic or lignocellulosic
materials, or starchy materials. These processes are described in
detail in U.S. Ser. No. 12/429,045.
[0104] In some embodiments, biomass can be processed by applying
two or more of any of the processes described herein, such Fenton
oxidation combined with any one, two or more of radiation,
sonication, oxidation, pyrolysis, and steam explosion either with
or without prior, intermediate, or subsequent physical feedstock
preparation. The processes can be applied in any order or
concurrently to the biomass. Multiple processes can in some cases
provide materials that can be more readily utilized by a variety of
microorganisms because of their lower molecular weight, lower
crystallinity, and/or enhanced solubility. Multiple processes can
provide synergies and can reduce overall energy input required in
comparison to any single process.
Primary Processing
[0105] Primary processing of the pretreated feedstock may include
bioprocesses such as saccharifying and/or fermenting the feedstock,
e.g., by contacting the pretreated material with an enzyme and/or
microorganism. Products produced by such contact can include any of
those products described herein, such as food or fuel, e.g.,
ethanol, or any other products described in U.S. Provisional
Application Ser. No. 61/139,453.
Fermentation
[0106] Generally, various microorganisms can produce a number of
useful products, such as a fuel, by operating on, e.g., fermenting
the pretreated biomass materials. For example, alcohols, organic
acids, hydrocarbons, hydrogen, proteins or mixtures of any of these
materials can be produced by fermentation or other
bioprocesses.
[0107] The microorganism can be a natural microorganism or an
engineered microorganism. For example, the microorganism can be a
bacterium, e.g., a cellulolytic bacterium, a fungus, e.g., a yeast,
a plant or a protist, e.g., an algae, a protozoa or a fungus-like
protist, e.g., a slime mold. When the organisms are compatible,
mixtures of organisms can be utilized.
[0108] To aid in the breakdown of the materials that include the
cellulose, one or more enzymes, e.g., a cellulolytic enzyme can be
utilized. In some embodiments, the materials that include the
cellulose are first treated with the enzyme, e.g., by combining the
material and the enzyme in an aqueous solution. This material can
then be combined with the microorganism. In other embodiments, the
materials that include the cellulose, the one or more enzymes and
the microorganism are combined concurrently, e.g., by combining in
an aqueous solution.
[0109] The pretreated material can be treated with heat and/or a
chemical (e.g., mineral acid, base or a strong oxidizer such as
sodium hypochlorite) to further facilitate breakdown.
[0110] During fermentation, sugars released from cellulolytic
hydrolysis or saccharification are fermented to, e.g., ethanol, by
a fermenting microorganism such as yeast. Suitable fermenting
microorganisms have the ability to convert carbohydrates, such as
glucose, xylose, arabinose, mannose, galactose, oligosaccharides or
polysaccharides into fermentation products. Fermenting
microorganisms include strains of the genus Sacchromyces spp. e.g.,
Sacchromyces cerevisiae (baker's yeast), Saccharomyces distaticus,
Saccharomyces uvarum; the genus Kluyveromyces, e.g., species
Kluyveromyces marxianus, Kluyveromyces fragilis; the genus Candida,
e.g., Candida pseudotropicalis, and Candida brassicae, the genus
Clavispora, e.g., species Clavispora lusitaniae and Clavispora
opuntiae the genus Pachysolen, e.g., species Pachysolen
tannophilus, the genus Bretannomyces, e.g., species Bretannomyces
clausenii (Philippidis, G. P., 1996, Cellulose bioconversion
technology, in Handbook on Bioethanol: Production and Utilization,
Wyman, C. E., ed., Taylor & Francis, Washington, D.C.,
179-212).
[0111] Commercially available yeasts include, for example, Red
Star.RTM./Lesaffre Ethanol Red (available from Red Star/Lesaffre,
USA) FALI.RTM. (available from Fleischmann's Yeast, a division of
Burns Philip Food Inc., USA), SUPERSTART.RTM. (available from
Alltech), GERT STRAND.RTM. (available from Gert Strand AB, Sweden)
and FERMOL.RTM. (available from DSM Specialties).
[0112] Bacteria that can ferment biomass to ethanol and other
products include, e.g., Zymomonas mobilis and Clostridium
thermocellum (Philippidis, 1996, supra). Leschine et al.
(International Journal of Systematic and Evolutionary Microbiology
2002, 52, 1155-1160) isolated an anaerobic, mesophilic,
cellulolytic bacterium from forest soil, Clostridium
phytofermentans sp. nov., which converts cellulose to ethanol.
[0113] Fermentation of biomass to ethanol and other products may be
carried out using certain types of thermophilic or genetically
engineered microorganisms, such Thermoanaerobacter species,
including T. mathranii, and yeast species such as Pichia species.
An example of a strain of T. mathranii is A3M4 described in
Sonne-Hansen et al. (Applied Microbiology and Biotechnology 1993,
38, 537-541) or Ahring et al. (Arch. Microbiol. 1997, 168,
114-119).
[0114] Yeast and Zymomonas bacteria can be used for fermentation or
conversion. The optimum pH for yeast is from about pH 4 to 5, while
the optimum pH for Zymomonas is from about pH 5 to 6. Typical
fermentation times are about 24 to 96 hours with temperatures in
the range of 26.degree. C. to 40.degree. C., however thermophilic
microorganisms prefer higher temperatures.
[0115] Enzymes and biomass-destroying organisms that break down
biomass, such as the cellulose and/or the lignin portions of the
biomass, to lower molecular weight of the carbohydrate-containing
materials contain or make various cellulolytic enzymes
(cellulases), ligninases or various small molecule
biomass-destroying metabolites. These enzymes may be a complex of
enzymes that act synergistically to degrade crystalline cellulose
or the lignin portions of biomass. Examples of cellulolytic enzymes
include: endoglucanases, cellobiohydrolases, and cellobiases
(.beta.-glucosidases). A cellulosic substrate is initially
hydrolyzed by endoglucanases at random locations producing
oligomeric intermediates. These intermediates are then substrates
for exo-splitting glucanases such as cellobiohydrolase to produce
cellobiose from the ends of the cellulose polymer. Cellobiose is a
water-soluble 1,4-linked dimer of glucose. Finally cellobiase
cleaves cellobiose to yield glucose.
[0116] A cellulase is capable of degrading biomass and may be of
fungal or bacterial origin. Suitable enzymes include cellulases
from the genera Bacillus, Pseudomonas, Humicola, Fusarium,
Thielavia, Acremonium, Chrysosporium and Trichoderma, and include
species of Humicola, Coprinus, Thielavia, Fusarium, Myceliophthora,
Acremonium, Cephalosporium, Scytalidium, Penicillium or Aspergillus
(see, e.g., EP 458162), especially those produced by a strain
selected from the species Humicola insolens (reclassified as
Scytalidium thermophilum, see, e.g., U.S. Pat. No. 4,435,307),
Coprinus cinereus, Fusarium oxysporum, Myceliophthora thermophile,
Meripilus giganteus, Thielavia terrestris, Acremonium sp.,
Acremonium persicinum, Acremonium acremonium, Acremonium
brachypenium, Acremonium dichromosporum, Acremonium obclavatum,
Acremonium pinkertoniae, Acremonium roseogriseum, Acremonium
incoloratum, and Acremonium furatum; preferably from the species
Humicola insolens DSM 1800, Fusarium oxysporum DSM 2672,
Myceliophthora thermophila CBS 117.65, Cephalosporium sp. RYM-202,
Acremonium sp. CBS 478.94, Acremonium sp. CBS 265.95, Acremonium
persicinum CBS 169.65, Acremonium acremonium AHU 9519,
Cephalosporium sp. CBS 535.71, Acremonium brachypenium CBS 866.73,
Acremonium dichromosporum CBS 683.73, Acremonium obclavatum CBS
311.74, Acremonium pinkertoniae CBS 157.70, Acremonium roseogriseum
CBS 134.56, Acremonium incoloratum CBS 146.62, and Acremonium
furatum CBS 299.70H. Cellulolytic enzymes may also be obtained from
Chrysosporium, preferably a strain of Chrysosporium lucknowense.
Additionally, Trichoderma (particularly Trichoderma viride,
Trichoderma reesei, and Trichoderma koningii), alkalophilic
Bacillus (see, for example, U.S. Pat. No. 3,844,890 and EP 458162),
and Streptomyces (see, e.g., EP 458162) may be used.
[0117] Anaerobic cellulolytic bacteria have also been isolated from
soil, e.g., a novel cellulolytic species of Clostridium,
Clostridium phytofermentans sp. nov. (see Leschine et. al,
International Journal of Systematic and Evolutionary Microbiology
(2002), 52, 1155-1160).
[0118] Cellulolytic enzymes using recombinant technology can also
be used (see, e.g., WO 2007/071818 and WO 2006/110891).
[0119] The cellulolytic enzymes used can be produced by
fermentation of the above-noted microbial strains on a nutrient
medium containing suitable carbon and nitrogen sources and
inorganic salts, using procedures known in the art (see, e.g.,
Bennett, J. W. and LaSure, L. (eds.), More Gene Manipulations in
Fungi, Academic Press, CA 1991). Suitable media are available from
commercial suppliers or may be prepared according to published
compositions (e.g., in catalogues of the American Type Culture
Collection). Temperature ranges and other conditions suitable for
growth and cellulase production are known in the art (see, e.g.,
Bailey, J. E., and Ollis, D. F., Biochemical Engineering
Fundamentals, McGraw-Hill Book Company, NY, 1986).
[0120] Treatment of cellulose with cellulase is usually carried out
at temperatures between 30.degree. C. and 65.degree. C. Cellulases
are active over a range of pH of about 3 to 7. A saccharification
step may last up to 120 hours. The cellulase enzyme dosage achieves
a sufficiently high level of cellulose conversion. For example, an
appropriate cellulase dosage is typically between 5.0 and 50 Filter
Paper Units (FPU or IU) per gram of cellulose. The FPU is a
standard measurement and is defined and measured according to Ghose
(1987, Pure and Appl. Chem. 59:257-268).
[0121] Mobile fermentors can be utilized, as described in U.S.
Provisional Patent Application Ser. 60/832,735, now Published
International Application No. WO 2008/011598.
Products/Co-Products
[0122] Using such primary processes and/or post-processing, the
treated biomass can be converted to one or more products, for
example alcohols, e.g., methanol, ethanol, propanol, isopropanol,
butanol, e.g., n-, sec- or t-butanol, ethylene glycol, propylene
glycol, 1,4-butane diol, glycerin or mixtures of these alcohols;
organic acids, such as formic acid, acetic acid, propionic acid,
butyric acid, valeric acid, caproic, palmitic acid, stearic acid,
oxalic acid, malonic acid, succinic acid, glutaric acid, oleic
acid, linoleic acid, glycolic acid, lactic acid,
.gamma.-hydroxybutyric acid or mixtures of these acids; food
products; animal feed; pharmaceuticals; or nutriceuticals.
Co-products that may be produced include lignin residue.
EXAMPLES
[0123] The following Examples are intended to illustrate, and do
not limit the teachings of this disclosure.
Example 1
Preparation of Fibrous Material from Polycoated Paper
[0124] A 1500 pound skid of virgin, half-gallon juice cartons made
of un-printed polycoated white Kraft board having a bulk density of
20 lb/ft.sup.3 was obtained from International Paper. Each carton
was folded flat, and then fed into a 3 hp Flinch Baugh shredder at
a rate of approximately 15 to 20 pounds per hour. The shredder was
equipped with two 12 inch rotary blades, two fixed blades and a
0.30 inch discharge screen. The gap between the rotary and fixed
blades was adjusted to 0.10 inch. The output from the shredder
resembled confetti having a width of between 0.1 inch and 0.5 inch,
a length of between 0.25 inch and 1 inch and a thickness equivalent
to that of the starting material (about 0.075 inch).
[0125] The confetti-like material was fed to a Munson rotary knife
cutter, Model SC30. Model SC30 is equipped with four rotary blades,
four fixed blades, and a discharge screen having 1/8 inch openings.
The gap between the rotary and fixed blades was set to
approximately 0.020 inch. The rotary knife cutter sheared the
confetti-like pieces across the knife-edges, tearing the pieces
apart and releasing a fibrous material at a rate of about one pound
per hour. The fibrous material had a BET surface area of 0.9748
m.sup.2/g+/-0.0167 m.sup.2/g, a porosity of 89.0437 percent and a
bulk density (@0.53 psia) of 0.1260 g/mL. An average length of the
fibers was 1.141 mm and an average width of the fibers was 0.027
mm, giving an average L/D of 42:1. A scanning electron micrograph
of the fibrous material is shown in FIG. 9 at 25.times.
magnification.
Example 2
Preparation of Fibrous Material from Bleached Kraft Board
[0126] A 1500 pound skid of virgin bleached white Kraft board
having a bulk density of 30 lb/ft.sup.3 was obtained from
International Paper. The material was folded flat, and then fed
into a 3 hp Flinch Baugh shredder at a rate of approximately 15 to
20 pounds per hour. The shredder was equipped with two 12 inch
rotary blades, two fixed blades and a 0.30 inch discharge screen.
The gap between the rotary and fixed blades was adjusted to 0.10
inch. The output from the shredder resembled confetti having a
width of between 0.1 inch and 0.5 inch, a length of between 0.25
inch and 1 inch and a thickness equivalent to that of the starting
material (about 0.075 inch). The confetti-like material was fed to
a Munson rotary knife cutter, Model SC30. The discharge screen had
1/8 inch openings. The gap between the rotary and fixed blades was
set to approximately 0.020 inch. The rotary knife cutter sheared
the confetti-like pieces, releasing a fibrous material at a rate of
about one pound per hour. The fibrous material had a BET surface
area of 1.1316 m.sup.2/g+/-0.0103 m.sup.2/g, a porosity of 88.3285
percent and a bulk density (@0.53 psia) of 0.1497 g/mL. An average
length of the fibers was 1.063 mm and an average width of the
fibers was 0.0245 mm, giving an average L/D of 43:1. A scanning
electron micrographs of the fibrous material is shown in FIG. 10 at
25.times. magnification.
Example 3
Preparation of Twice Sheared Fibrous Material from Bleached Kraft
Board
[0127] A 1500 pound skid of virgin bleached white Kraft board
having a bulk density of 30 lb/ft.sup.3 was obtained from
International Paper. The material was folded flat, and then fed
into a 3 hp Flinch Baugh shredder at a rate of approximately 15 to
20 pounds per hour. The shredder was equipped with two 12 inch
rotary blades, two fixed blades and a 0.30 inch discharge screen.
The gap between the rotary and fixed blades was adjusted to 0.10
inch. The output from the shredder resembled confetti (as above).
The confetti-like material was fed to a Munson rotary knife cutter,
Model SC30. The discharge screen had 1/16 inch openings. The gap
between the rotary and fixed blades was set to approximately 0.020
inch. The rotary knife cutter the confetti-like pieces, releasing a
fibrous material at a rate of about one pound per hour. The
material resulting from the first shearing was fed back into the
same setup described above and sheared again. The resulting fibrous
material had a BET surface area of 1.4408 m.sup.2/g+/-0.0156
m.sup.2/g, a porosity of 90.8998 percent and a bulk density (@0.53
psia) of 0.1298 g/mL. An average length of the fibers was 0.891 mm
and an average width of the fibers was 0.026 mm, giving an average
L/D of 34:1. A scanning electron micrograph of the fibrous material
is shown in FIG. 11 at 25.times. magnification.
Example 4
Preparation of Thrice Sheared Fibrous Material from Bleached Kraft
Board
[0128] A 1500 pound skid of virgin bleached white Kraft board
having a bulk density of 30 lb/ft.sup.3 was obtained from
International Paper. The material was folded flat, and then fed
into a 3 hp Flinch Baugh shredder at a rate of approximately 15 to
20 pounds per hour. The shredder was equipped with two 12 inch
rotary blades, two fixed blades and a 0.30 inch discharge screen.
The gap between the rotary and fixed blades was adjusted to 0.10
inch. The output from the shredder resembled confetti (as above).
The confetti-like material was fed to a Munson rotary knife cutter,
Model SC30. The discharge screen had 1/8 inch openings. The gap
between the rotary and fixed blades was set to approximately 0.020
inch. The rotary knife cutter sheared the confetti-like pieces
across the knife-edges. The material resulting from the first
shearing was fed back into the same setup and the screen was
replaced with a 1/16 inch screen. This material was sheared. The
material resulting from the second shearing was fed back into the
same setup and the screen was replaced with a 1/32 inch screen.
This material was sheared. The resulting fibrous material had a BET
surface area of 1.6897 m.sup.2/g+/-0.0155 m.sup.2/g, a porosity of
87.7163 percent and a bulk density (@0.53 psia) of 0.1448 g/mL. An
average length of the fibers was 0.824 mm and an average width of
the fibers was 0.0262 mm, giving an average L/D of 32:1. A scanning
electron micrograph of the fibrous material is shown in FIG. 12 at
25.times. magnification.
Example 5
Methods of Determining Molecular Weight of Cellulosic and
Lignocellulosic Materials by Gel Permeation Chromatography
[0129] Cellulosic and lignocellulosic materials for analysis were
treated according to Example 4. Sample materials presented in the
following tables include Kraft paper (P), wheat straw (WS), alfalfa
(A), and switchgrass (SG). The number "132" of the Sample ID refers
to the particle size of the material after shearing through a 1/32
inch screen. The number after the dash refers to the dosage of
radiation (MRad) and "US" refers to ultrasonic treatment. For
example, a sample ID "P132-10" refers to Kraft paper that has been
sheared to a particle size of 132 mesh and has been irradiated with
10 MRad.
TABLE-US-00001 TABLE 1 Peak Average Molecular Weight of Irradiated
Kraft Paper Sample Dosage.sup.1 Average MW .+-. Source Sample ID
(MRad) Ultrasound.sup.2 Std Dev. Kraft Paper P132 0 No 32853 .+-.
10006 P132-10 10 '' 61398 .+-. 2468** P132-100 100 '' 8444 .+-. 580
P132-181 181 '' 6668 .+-. 77 P132-US 0 Yes 3095 .+-. 1013 **Low
doses of radiation appear to increase the molecular weight of some
materials .sup.1Dosage Rate = 1 MRad/hour .sup.2Treatment for 30
minutes with 20 kHz ultrasound using a 1000 W horn under
re-circulating conditions with the material dispersed in water.
TABLE-US-00002 TABLE 2 Peak Average Molecular Weight of Irradiated
Materials Dosage.sup.1 Average MW .+-. Sample ID Peak # (MRad)
Ultrasound.sup.2 Std Dev. WS132 1 0 No 1407411 .+-. 175191 2 '' ''
39145 .+-. 3425 3 '' '' 2886 .+-. 177 WS132-10* 1 10 '' 26040 .+-.
3240 WS132-100* 1 100 '' 23620 .+-. 453 A132 1 0 '' 1604886 .+-.
151701 2 '' '' 37525 .+-. 3751 3 '' '' 2853 .+-. 490 A132-10* 1 10
'' 50853 .+-. 1665 2 '' '' 2461 .+-. 17 A132-100* 1 100 '' 38291
.+-. 2235 2 '' '' 2487 .+-. 15 SG132 1 0 '' 1557360 .+-. 83693 2 ''
'' 42594 .+-. 4414 3 '' '' 3268 .+-. 249 SG132-10* 1 10 '' 60888
.+-. 9131 SG132-100* 1 100 '' 22345 .+-. 3797 SG132-10-US 1 10 Yes
86086 .+-. 43518 2 '' '' 2247 .+-. 468 SG132-100-US 1 100 '' 4696
.+-. 1465 *Peaks coalesce after treatment **Low doses of radiation
appear to increase the molecular weight of some materials
.sup.1Dosage Rate = 1 MRad/hour .sup.2Treatment for 30 minutes with
20 kHz ultrasound using a 1000 W horn under re-circulating
conditions with the material dispersed in water.
[0130] Gel Permeation Chromatography (GPC) is used to determine the
molecular weight distribution of polymers. During GPC analysis, a
solution of the polymer sample is passed through a column packed
with a porous gel trapping small molecules. The sample is separated
based on molecular size with larger molecules eluting sooner than
smaller molecules. The retention time of each component is most
often detected by refractive index (RI), evaporative light
scattering (ELS), or ultraviolet (UV) and compared to a calibration
curve. The resulting data is then used to calculate the molecular
weight distribution for the sample.
[0131] A distribution of molecular weights rather than a unique
molecular weight is used to characterize synthetic polymers. To
characterize this distribution, statistical averages are utilized.
The most common of these averages are the "number average molecular
weight" (M.sub.n) and the "weight average molecular weight"
(MO.
[0132] M.sub.n is similar to the standard arithmetic mean
associated with a group of numbers. When applied to polymers,
M.sub.n refers to the average molecular weight of the molecules in
the polymer. M.sub.n is calculated affording the same amount of
significance to each molecule regardless of its individual
molecular weight. The average M.sub.n is calculated by the
following formula where N.sub.i is the number of molecules with a
molar mass equal to
M _ n = i N i M i i N i ##EQU00001##
[0133] M.sub.w is another statistical descriptor of the molecular
weight distribution that places a greater emphasis on larger
molecules than smaller molecules in the distribution. The formula
below shows the statistical calculation of the weight average
molecular weight.
M _ w = i N i M i 2 i N i M i ##EQU00002##
[0134] The polydispersity index or PI is defined as the ratio of
M.sub.W/M.sub.n. The larger the PI, the broader or more disperse
the distribution. The lowest value that a PI can be is 1. This
represents a monodisperse sample; that is, a polymer with all of
the molecules in the distribution being the same molecular
weight.
[0135] The peak molecular weight value (M.sub.P) is another
descriptor defined as the mode of the molecular weight
distribution. It signifies the molecular weight that is most
abundant in the distribution. This value also gives insight to the
molecular weight distribution.
[0136] Most GPC measurements are made relative to a different
polymer standard. The accuracy of the results depends on how
closely the characteristics of the polymer being analyzed match
those of the standard used. The expected error in reproducibility
between different series of determinations, calibrated separately,
is ca. 5-10% and is characteristic to the limited precision of GPC
determinations. Therefore, GPC results are most useful when a
comparison between the molecular weight distribution of different
samples is made during the same series of determinations.
[0137] The lignocellulosic samples required sample preparation
prior to GPC analysis. First, a saturated solution (8.4% by weight)
of lithium chloride (LiCl) was prepared in dimethyl acetamide
(DMAc). Approximately 100 mg of the sample was added to
approximately 10 g of a freshly prepared saturated LiCl/DMAc
solution, and the mixture was heated to approximately 150.degree.
C.-170.degree. C. with stirring for 1 hour. The resulting solutions
were generally light- to dark-yellow in color. The temperature of
the solutions were decreased to approximately 100.degree. C. and
heated for an additional 2 hours. The temperature of the solutions
were then decreased to approximately 50.degree. C. and the sample
solution was heated for approximately 48 to 60 hours. Of note,
samples irradiated at 100 MRad were more easily solubilized as
compared to their untreated counterpart. Additionally, the sheared
samples (denoted by the number 132) had slightly lower average
molecular weights as compared with uncut samples.
[0138] The resulting sample solutions were diluted 1:1 using DMAc
as solvent and were filtered through a 0.45 .mu.m PTFE filter. The
filtered sample solutions were then analyzed by GPC. The peak
average molecular weight (Mp) of the samples, as determined by Gel
Permeation Chromatography (GPC), are summarized in Tables 1 and 2.
Each sample was prepared in duplicate and each preparation of the
sample was analyzed in duplicate (two injections) for a total of
four injections per sample. The EasiCal.RTM. polystyrene standards
PS1A and PS1B were used to generate a calibration curve for the
molecular weight scale from about 580 to 7,500,00 Daltons. Table 3
recites the GPC analysis conditions.
TABLE-US-00003 TABLE 3 GPC Analysis Conditions Instrument: Waters
Alliance GPC 2000 Plgel 10.mu. Mixed-B Columns (3): S/N's:
10M-MB-148-83; 10M-MB- 148-84; 10M-MB-174-129 Mobile Phase
(solvent): 0.5% LiCl in DMAc (1.0 mL/min.) Column/Detector
Temperature: 70.degree. C. Injector Temperature: 70.degree. C.
Sample Loop Size: 323.5 .mu.L
Example 6
Porosimetry Analysis of Irradiated Materials
[0139] Mercury pore size and pore volume analysis (Table 4) is
based on forcing mercury (a non-wetting liquid) into a porous
structure under tightly controlled pressures. Since mercury does
not wet most substances and will not spontaneously penetrate pores
by capillary action, it must be forced into the voids of the sample
by applying external pressure. The pressure required to fill the
voids is inversely proportional to the size of the pores. Only a
small amount of force or pressure is required to fill large voids,
whereas much greater pressure is required to fill voids of very
small pores.
TABLE-US-00004 TABLE 4 Pore Size and Volume Distribution by Mercury
Porosimetry Median Median Average Bulk Total Total Pore Pore Pore
Density Apparent Intrusion Pore Diameter Diameter Diameter @ 0.50
(skeletal) Volume Area (Volume) (Area) (4 V/A) psia Density
Porosity Sample ID (mL/g) (m.sup.2/g) (.mu.m) (.mu.m) (.mu.m)
(g/mL) (g/mL) (%) P132 6.0594 1.228 36.2250 13.7278 19.7415 0.1448
1.1785 87.7163 P132-10 5.5436 1.211 46.3463 4.5646 18.3106 0.1614
1.5355 89.4875 P132-100 5.3985 0.998 34.5235 18.2005 21.6422 0.1612
1.2413 87.0151 P132-181 3.2866 0.868 25.3448 12.2410 15.1509 0.2497
1.3916 82.0577 P132-US 6.0005 14.787 98.3459 0.0055 1.6231 0.1404
0.8894 84.2199 A132 2.0037 11.759 64.6308 0.0113 0.6816 0.3683
1.4058 73.7990 A132-10 1.9514 10.326 53.2706 0.0105 0.7560 0.3768
1.4231 73.5241 A132-100 1.9394 10.205 43.8966 0.0118 0.7602 0.3760
1.3889 72.9264 SG132 2.5267 8.265 57.6958 0.0141 1.2229 0.3119
1.4708 78.7961 SG132-10 2.1414 8.643 26.4666 0.0103 0.9910 0.3457
1.3315 74.0340 SG132-100 2.5142 10.766 32.7118 0.0098 0.9342 0.3077
1.3590 77.3593 SG132-10-US 4.4043 1.722 71.5734 1.1016 10.2319
0.1930 1.2883 85.0169 SG132-100-US 4.9665 7.358 24.8462 0.0089
2.6998 0.1695 1.0731 84.2010 WS132 2.9920 5.447 76.3675 0.0516
2.1971 0.2773 1.6279 82.9664 WS132-10 3.1138 2.901 57.4727 0.3630
4.2940 0.2763 1.9808 86.0484 WS132-100 3.2077 3.114 52.3284 0.2876
4.1199 0.2599 1.5611 83.3538
[0140] The AutoPore.RTM. 9520 can attain a maximum pressure of 414
MPa or 60,000 psia. There are four low pressure stations for sample
preparation and collection of macropore data from 0.2 psia to 50
psia. There are two high pressure chambers which collects data from
25 psia to 60,000 psia. The sample is placed in a bowl-like
apparatus called a penetrometer, which is bonded to a glass
capillary stem with a metal coating. As mercury invades the voids
in and around the sample, it moves down the capillary stem. The
loss of mercury from the capillary stem results in a change in the
electrical capacitance. The change in capacitance during the
experiment is converted to volume of mercury by knowing the stem
volume of the penetrometer in use. A variety of penetrometers with
different bowl (sample) sizes and capillaries are available to
accommodate most sample sizes and configurations. Table 5 below
defines some of the key parameters calculated for each sample.
TABLE-US-00005 TABLE 5 Definition of Parameters Parameter
Description Total Intrusion Volume: The total volume of mercury
intruded during an experiment. This can include interstitial
filling between small particles, porosity of sample, and
compression volume of sample. Total Pore Area: The total intrusion
volume converted to an area assuming cylindrical shaped pores.
Median Pore Diameter The size at the 50.sup.th percentile (volume):
on the cumulative volume graph. Median Pore Diameter (area): The
size at the 50.sup.th percentile on the cumulative area graph.
Average Pore Diameter: The total pore volume divided by the total
pore area (4 V/A). Bulk Density: The mass of the sample divided by
the bulk volume. Bulk volume is determined at the filling pressure,
typically 0.5 psia. Apparent Density: The mass of sample divided by
the volume of sample measured at highest pressure, typically 60,000
psia. Porosity: (Bulk Density/Apparent Density) .times. 100%
Example 7
Particle Size Analysis of Irradiated Materials
[0141] The technique of particle sizing by static light scattering
is based on Mie theory (which also encompasses Fraunhofer theory).
Mie theory predicts the intensity vs. angle relationship as a
function of the size for spherical scattering particles provided
that other system variables are known and held constant. These
variables are the wavelength of incident light and the relative
refractive index of the sample material. Application of Mie theory
provides the detailed particle size information. Table 6 summarizes
particle size using median diameter, mean diameter, and modal
diameter as parameters.
TABLE-US-00006 TABLE 6 Particle Size by Laser Light Scattering (Dry
Sample Dispersion) Median Diameter Mean Diameter Modal Diameter
Sample ID (.mu.m) (.mu.m) (.mu.m) A132 380.695 418.778 442.258
A132-10 321.742 366.231 410.156 A132-100 301.786 348.633 444.169
SG132 369.400 411.790 455.508 SG132-10 278.793 325.497 426.717
SG132-100 242.757 298.686 390.097 WS132 407.335 445.618 467.978
WS132-10 194.237 226.604 297.941 WS132-100 201.975 236.037
307.304
[0142] Particle size was determined by Laser Light Scattering (Dry
Sample Dispersion) using a Malvern Mastersizer 2000 using the
following conditions:
TABLE-US-00007 Feed Rate: 35% Disperser Pressure: 4 Bar Optical
Model: (2.610, 1.000i), 1.000
[0143] An appropriate amount of sample was introduced onto a
vibratory tray. The feed rate and air pressure were adjusted to
ensure that the particles were properly dispersed. The key
component is selecting an air pressure that will break up
agglomerations, but does not compromise the sample integrity. The
amount of sample needed varies depending on the size of the
particles. In general, samples with fine particles require less
material than samples with coarse particles.
Example 8
Surface Area Analysis of Irradiated Materials
[0144] Surface area of each sample was analyzed using a
Micromeritics.RTM. ASAP 2420 Accelerated Surface Area and
Porosimetry System. The samples were prepared by first degassing
for 16 hours at 40.degree. C. Next, free space (both warm and cold)
with helium is calculated and then the sample tube is evacuated
again to remove the helium. Data collection begins after this
second evacuation and consists of defining target pressures which
controls how much gas is dosed onto the sample. At each target
pressure, the quantity of gas adsorbed and the actual pressure are
determined and recorded. The pressure inside the sample tube is
measured with a pressure transducer. Additional doses of gas will
continue until the target pressure is achieved and allowed to
equilibrate. The quantity of gas adsorbed is determined by summing
multiple doses onto the sample. The pressure and quantity define a
gas adsorption isotherm and are used to calculate a number of
parameters, including BET surface area (Table 7).
TABLE-US-00008 TABLE 7 Summary of Surface Area by Gas Adsorption
BET Surface Sample ID Single point surface area (m.sup.2/g) Area
(m.sup.2/g) P132 @ P/Po = 0.250387771 1.5253 1.6897 P132-10 @ P/Po
= 0.239496722 1.0212 1.2782 P132-100 @ P/Po = 0.240538100 1.0338
1.2622 P132-181 @ P/Po = 0.239166091 0.5102 0.6448 P132-US @ P/Po =
0.217359072 1.0983 1.6793 A132 @ P/Po = 0.240040610 0.5400 0.7614
A132-10 @ P/Po = 0.211218936 0.5383 0.7212 A132-100 @ P/Po =
0.238791097 0.4258 0.5538 SG132 @ P/Po = 0.237989353 0.6359 0.8350
SG132-10 @ P/Po = 0.238576905 0.6794 0.8689 SG132-100 @ P/Po =
0.241960361 0.5518 0.7034 SG132-10-US @ P/Po = 0.225692889 0.5693
0.7510 SG132-100-US @ P/Po = 0.225935246 1.0983 1.4963 WS132 @ P/Po
= 0.237823664 0.6582 0.8663 WS132-10 @ P/Po = 0.238612476 0.6191
0.7912 WS132-100 @ P/Po = 0.238398832 0.6255 0.8143
[0145] The BET model for isotherms is a widely used theory for
calculating the specific surface area. The analysis involves
determining the monolayer capacity of the sample surface by
calculating the amount required to cover the entire surface with a
single densely packed layer of krypton. The monolayer capacity is
multiplied by the cross sectional area of a molecule of probe gas
to determine the total surface area. Specific surface area is the
surface area of the sample aliquot divided by the mass of the
sample.
Example 9
Fiber Length Determination of Irradiated Materials
[0146] Fiber length distribution testing was performed in
triplicate on the samples submitted using the Techpap MorFi LB01
system. The average length and width are reported in Table 8.
TABLE-US-00009 TABLE 8 Summary of Lignocellulosic Fiber Length and
Width Data Average Statistically Length Corrected Arithmetic
Weighted Average Length Width Average in Length Weighted in
(micrometers) Sample ID (mm) (mm) Length (mm) (.mu.m) P132-10 0.484
0.615 0.773 24.7 P132-100 0.369 0.423 0.496 23.8 P132-181 0.312
0.342 0.392 24.4 A132-10 0.382 0.423 0.650 43.2 A132-100 0.362
0.435 0.592 29.9 SG132-10 0.328 0.363 0.521 44.0 SG132-100 0.325
0.351 0.466 43.8 WS132-10 0.353 0.381 0.565 44.7 WS132-100 0.354
0.371 0.536 45.4
Other Embodiments
[0147] A number of embodiments of the invention have been
described. Nevertheless, it will be understood that various
modifications may be made without departing from the spirit and
scope of the invention.
Lignases and Biomass Destroying Enzymes
[0148] For example, some methods utilize one or more ligninases
and/or biomass-destroying enzymes, instead of or in addition to
Fenton chemistry, to reduce recalcitrance in cellulosic or
lignocellulosic materials. In such methods, a first cellulosic or
lignocellulosic material having a first level of recalcitrance is
provided and combined with one or more ligninases and/or one or
more biomass-destroying, e.g., lignin-destroying organisms, so as
to contact the first cellulosic or lignocellulosic material. The
contact is maintained for a period of time, such as between 2 and
24 hours, e.g., between 6 and 12 hours, and under conditions
sufficient, e.g., below a pH of about 6, such as between pH 3 and
5.5, to produce a second lignocellulosic material having a second
level of recalcitrance lower than the first level of recalcitrance.
After reduction of the recalcitrance, the second cellulosic or
lignocellulosic material can be contacted with one or more enzymes
and/or microorganisms, e.g., to make any product described herein,
e.g., food or fuel, e.g., ethanol or butanol (e.g., n-butanol) or
any product described in any application incorporated by reference
herein.
[0149] The ligninase can be, e.g., one or more of manganese
peroxidase, lignin peroxidase or laccases.
[0150] In particular implementations, the biomass-destroying
organism can be, e.g., one or more of white rot, brown rot or soft
rot. For example, the biomass-destroying organism can be a
Basidiomycetes fungus. In particular embodiments, the
biomass-destroying organism Phanerochaete chrysoporium or
Gleophyllum trabeum.
[0151] Ligninases, biomass-destroying organisms and small molecule
metabolites are described in Kirk et al., Enzyme Microb. Technol.
1986, vol. 8, 27-32, Kirk et al., Enzymes for Pulp and Paper
Processing, Chapter 1 (Roles for Microbial Enzymes in Pulp and
Paper Processing and Kirk et al., The Chemistry of Solid Wood,
Chapter 12 (Biological Decomposition of Solid Wood (pp.
455-487).
Hydrocarbon-Containing Materials
[0152] In some embodiments, the methods and systems disclosed
herein can be used to process hydrocarbon-containing materials such
as tar or oil sands, oil shale, crude oil (e.g., heavy crude oil
and/or light crude oil), bitumen, coal, petroleum gases (e.g.,
methane, ethane, propane, butane, isobutane), liquefied natural
and/or synthetic gas, asphalt, and other natural materials that
include various types of hydrocarbons. For example, a processing
facility for hydrocarbon-containing materials receives a supply of
raw material. The raw material can be delivered directly from a
mine, e.g., by conveyor belt and/or rail car system, and in certain
embodiments, the processing facility can be constructed in
relatively close proximity to, or even atop, the mine. In some
embodiments, the raw material can be transported to the processing
facility via railway freight car or another motorized transport
system, and/or pumped to the processing facility via pipeline.
[0153] When the raw material enters the processing facility, the
raw material can be broken down mechanically and/or chemically to
yield starting material. As an example, the raw material can
include material derived from oil sands and containing crude
bitumen. Bitumen can then be processed into one or more hydrocarbon
products using the methods disclosed herein. In some embodiments,
the oil sands material can be extracted from surface mines such as
open pit mines. In certain embodiments, sub-surface oil sands
material can be extracted using a hot water flotation process that
removes oil from sand particles, and then adding naphtha to allow
pumping of the oil to the processing facility.
[0154] Bitumen processing generally includes two stages. In a first
stage, relatively large bitumen hydrocarbons are cracked into
smaller molecules using coking, hydrocracking, or a combination of
the two techniques. In the coking process, carbon is removed from
bitumen hydrocarbon molecules at high temperatures (e.g.,
400.degree. C. or more), leading to cracking of the molecules. In
hydrocracking, hydrogen is added to bitumen molecules, which are
then cracked over a catalyst system (e.g., platinum).
[0155] In a second stage, the cracked bitumen molecules are
hydrotreated. In general, hydrotreating includes heating the
cracked bitumen molecules in a hydrogen atmosphere to remove
metals, nitrogen (e.g., as ammonia), and sulfur (e.g., as elemental
sulfur).
[0156] The overall bitumen processing procedure typically produces
approximately one barrel of synthetic crude oil for every 2.5 tons
of oil sand material processed. Moreover, an energy equivalent of
approximately one barrel of oil is used to produce three barrels of
synthetic crude oil from oil sand-derived bitumen sources.
[0157] As another example, oil shale typically includes
fine-grained sedimentary rock that includes significant amounts of
kerogen (a mixture of various organic compounds in solid form). By
heating oil shale, a vapor is liberated which can be purified to
yield a hydrocarbon rich shale oil and a combustible hydrocarbon
shale gas. Typically, the oil shale is heated to between
250.degree. C. and 550.degree. C. in the absence of oxygen to
liberate the vapor.
[0158] The efficiency and cost-effectiveness with which usable
hydrocarbon products can be extracted from oil sands material, oil
shale, crude oil, and other oil-based raw materials can be improved
by applying the methods disclosed herein. In addition, a variety of
different hydrocarbon products (including various hydrocarbon
fractions that are present in the raw material, and other types of
hydrocarbons that are formed during processing) can be extracted
from the raw materials.
[0159] In certain embodiments, in addition to Fenten oxidation,
other methods can also be used to process raw and/or intermediate
hydrocarbon-containing materials. For example, electron beams or
ion beams can be used to process the materials. For example, ion
beams that include one or more different types of ions (e.g.,
protons, carbon ions, oxygen ions, hydride ions) can be used to
process raw materials. The ion beams can include positive ions
and/or negative ions, in doses that vary from 1 Mrad to 2500 Mrad
or more, e.g., 50, 100, 250, 350, 500, 1000, 1500, 2000, or 2500
MRad, or even higher levels.
[0160] Other additional processing methods can be used, including
oxidation, pyrolysis, and sonication. In general, process
parameters for each of these techniques when treating
hydrocarbon-based raw and/or intermediate materials can be the same
as those disclosed above in connection with biomass materials.
Various combinations of these techniques can also be used to
process raw or intermediate materials.
[0161] Generally, the various techniques can be used in any order,
and any number of times, to treat raw and/or intermediate
materials. For example, to process bitumen from oil sands, one or
more of the techniques disclosed herein can be used prior to any
mechanical breakdown steps, following one or more mechanical
breakdown steps, prior to cracking, after cracking and/or prior to
hydrotreatment, and after hydrotreatment. As another example, to
process oil shale, one or more of the techniques disclosed herein
can be used prior to either or both of the vaporization and
purification steps discussed above. Products derived from the
hydrocarbon-based raw materials can be treated again with any
combination of techniques prior to transporting the products out of
the processing facility (e.g., either via motorized transport, or
via pipeline).
[0162] The techniques disclosed herein can be applied to process
raw and/or intermediate material in dry form, in a solution or
slurry, or in gaseous form (e.g., to process hydrocarbon vapors at
elevated temperature). The solubility of raw or intermediate
products in solutions and slurries can be controlled through
selective addition of one or more agents such as acids, bases,
oxidizing agents, reducing agents, and salts. In general, the
methods disclosed herein can be used to initiate and/or sustain the
reaction of raw and/or intermediate hydrocarbon-containing
materials, extraction of intermediate materials from raw materials
(e.g., extraction of hydrocarbon components from other solid or
liquid components), distribution of raw and/or intermediate
materials, and separation of intermediate materials from raw
materials (e.g., separation of hydrocarbon-containing components
from other solid matrix components to increase the concentration
and/or purity and/or homogeneity of the hydrocarbon
components).
[0163] In addition, microorganisms can be used for processing raw
or intermediate materials, either prior to or following the use of
the methods described herein. Suitable microorganisms include
various types of bacteria, yeasts, and mixtures thereof, as
disclosed previously. The processing facility can be equipped to
remove harmful byproducts that result from the processing of raw or
intermediate materials, including gaseous products that are harmful
to human operators, and chemical byproducts that are harmful to
humans and/or various microorganisms.
[0164] In some embodiments, the use of one or more of the
techniques disclosed herein results in a molecular weight reduction
of one or more components of the raw or intermediate material that
is processed. As a result, various lower weight hydrocarbon
substances can be produced from one or more higher weight
hydrocarbon substances. In certain embodiments, the use of one or
more of the techniques disclosed herein results in an increase in
molecular weight of one or more components of the raw or
intermediate material that is processed. For example, the various
techniques disclosed herein can induce bond-formation between
molecules of the components, leading to the formation of increased
quantities of certain products, and even to new, higher molecular
weight products. In addition to hydrocarbon products, various other
compounds can be extracted from the raw materials, including
nitrogen based compounds (e.g., ammonia), sulfur-based compounds,
and silicates and other silicon-based compounds. In certain
embodiments, one or more products extracted from the raw materials
can be combusted to generate process heat for heating water, raw or
intermediate materials, generating electrical power, or for other
applications.
[0165] Processing oil sand materials (including bitumen) using one
or more of the techniques disclosed herein can lead to more
efficient cracking and/or hydrotreatment of the bitumen. As another
example, processing oil shale can lead to more efficient extraction
of various products, including shale oil and/or shale gas, from the
oil shale. In certain embodiments, steps such as cracking or
vaporization may not even be necessary if the techniques disclosed
herein are first used to treat the raw material. Further, in some
embodiments, by treating raw and/or intermediate materials, the
products can be made more soluble in certain solvents, in
preparation for subsequent processing steps in solution (e.g.,
steam blasting, sonication). Improving the solubility of the
products can improve the efficiency of subsequent solution-based
treatment steps. By improving the efficiency of other processing
steps (e.g., cracking and/or hydrotreatment of bitumen,
vaporization of oil shale), the overall energy consumed in
processing the raw materials can be reduced, making extraction and
processing of the raw materials economically feasible.
[0166] Accordingly, other embodiments are within the scope of the
following claims.
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